Dietary proteins are linked to the pathogenic Escherichia coli (E. coli) through the intestinal tract, which is the site where both dietary proteins are metabolized and pathogenic E. coli strains play a pathogenic role. Dietary proteins are degraded by enzymes in the intestine lumen and their metabolites are transferred into enterocytes to be further metabolized. Seven diarrheagenic E. coli pathotypes have been identified, and they damage the intestinal epithelium through physical injury and effector proteins, which lead to inhibit the digestibility and absorption of dietary proteins in the intestine tract. But the increased tryptophan (Trp) content in the feed, low-protein diet or milk fractions supplementation is effective in preventing and controlling infections by pathogenic E. coli in the intestine.

膳食蛋白通过肠道与致病性大肠杆菌（E. coli）相连，肠道是两种膳食蛋白都被代谢的部位，致病性E. coli菌株发挥致病作用。饮食蛋白在肠腔中被酶降解，其代谢物转移到肠上皮细胞中进一步代谢。已鉴定出七种引起腹泻的大肠杆菌病原体，它们通过物理损伤和效应蛋白破坏肠道上皮，从而抑制肠道内饮食蛋白的消化和吸收。但是，饲料，低蛋白饮食或牛奶补充物中色氨酸（Trp）含量的增加可有效预防和控制肠道中病原性大肠杆菌的感染。